Chronic ischemic heart disease: pathogenesis, microscopic & gross pathomorphology; systemic and organ-specific manifestations
Chronic IHD is a form of progressive heart failure due to ischemic myocardial damage, often with the background of previous MI. Chronic IHD occurs when compensatory mechanisms (e.g. hypertrophy) for the MI fail.
Typically patients display left ventricular dilation with hypertrophy, with moderate to severe atherosclerosis of the coronary arteries. Histopathologically, we see fibrosis and subendocardial myocyte vacuolization due to chronic ischemia and previous MI. The gross pathology we would expect to show previous MI scars on the myocardium.
Old (healed) myocardial infarction: pale grey-white fibrous scar in the posterior left ventricular wall (arrow), the typical background of chronic IHD.
Image: “Gross pathology of old myocardial infarction” by Mikael Häggström, M.D. Author info - Reusing images - Conflicts of interest: None Mikael Häggström, M.D. Consent note, CC0, via Wikimedia Commons.
Remember: the organ changes of chronic heart failure:
- Left-sided: pulmonary congestion and oedema, haemosiderin-laden macrophages in the alveoli ("heart failure cells"), brown induration of the lungs
- Right-sided: chronic passive congestion of the liver ("nutmeg liver", later cardiac sclerosis), congestive splenomegaly, peripheral oedema, pleural effusion, ascites
- Low output: reduced kidney perfusion (prerenal azotaemia) and hypoxic damage to the brain
For pathogenesis, see acute IHD and Atherosclerosis, as this is simply the chronic form of this.
In summary, it’s HF (remember the symptoms), it’s chronic, it’s due to ischemic changes (see above pathohistology).